1. Field of the Invention
This invention relates to a firearm comprising a housing, a barrel, a chamber structure and a firing mechanism including a trigger, wherein the chamber structure is constituted by a chamber member, which is separate from the barrel and is slidably guided in the housing transversely to the barrel axis for reciprocation between a firing position and a loading position, when the chamber member is in its firing position the chamber at one end thereof coaxially adjoins the barrel and at the other end is closed by a closing wall of the housing, and when the chamber member is in its loading position both ends of the chamber are spaced from the barrel and the closing wall.
2. Description of the Prior Art
In most known firearms the barrel defines also a chamber for receiving the projectile or cartridge and a breechblock is longitudinally guided in the housing to seal the chamber on the rear so that the projectile can be propelled forwardly through the barrel. But such firearms have complicated breech-closing and firing mechanisms, which are composed of a large number of members, which can be manufactured only at high cost and result in a considerable overall length of the firearm and are liable to be deranged even when they are made and assembled with high precision.
AT-A-26,115, FR-A-317,851 and US-A-658,010 disclose firearms which have separate chamber members, which define a chamber and are reciprocable between a firing position for the discharge of a round and a loading position for receiving a cartridge. The chamber may be open only at one end for a firing of a caseless cartridge or may be open at both ends for a firing of a cartridge having a case. Said chamber members must be actuated by a springbiased rocker mechanism, which is incorporated in the firing mechanism, and the trigger can be operated at the same time to cock and actuate a firing pin of the firing mechanism so that the mechanism is also rather complicated and unreliable and the firearm cannot be used at all for military purposes.
DE-B-24 01 543 and DE-C-24 13 615 disclose a drum-shaped chamber member, which is rotatably mounted in the housing and is rotated through an angle of 90 degrees to move the chamber from its loading position to its firing position. Such rotary drums have not proved satisfactory in practice because they require the provision of expensive actuating, controlling and firing mechanisms and give rise to great difficulties when the cartridge case must be ejected because they must be moved to a special ejecting position for that purpose or the cartridge case that remained in the chamber or a cartridge that has not been fired must be pushed back from the chamber into the magazine.
In other known firearms the magazine defines also a chamber in which the cartridge is fired. Such firearms may have a rotatable drum magazine, e.g., in a revolver, or as disclosed in CA-A-1,056,631 and FR-A-347,965 may have a transversely displaceable bar magazine, which can repeatedly be advanced in the same direction to move consecutive cartridges to a firing position, in which the cartridge is axially aligned with the barrel and can be fired by a centering mechanism. In such firearms the chamber member is not a part of the firearm proper so that it is difficult to seal the chamber and, because the magazines may easily be damaged, the firearms are often jammed and liable to other functional disturbances.
The ammunition for use with the known firearms described hereinbefore must consist of caseless cartridges in those firearms from which cartridge cases cannot be ejected or can be ejected only with difficulty, although said caseless cartridges have not proved satisfactory, or the ammunition must consist of metal-cased cartridges in those firearms in which the chamber is only poorly sealed. The advantageous cartridges having plastic cases cannot be used in any of said known firearms.